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(No Model.) A. D. LINN 85 R. W. IRWIN.

BACK LOCK FASTENING FOR UHAIRS.

No. 576,206. Patented Feb. 2, 1897.

UNITED STATES PATENT OEEIcE.

ALLEN D. LINN AND ROBERT IV. IRWIN, OF GRAND RAPIDS, MICHIGAN,

ASSIGNORS TO THE GRAND RAPIDS OF SAME PLACE.

SCHOOL FURNITURE COMPANY,

SPECIFICATION forming part of Letters Patent NO. 576,206, dated February 2, 1897. Applieation filed May 21, 1896. Serial No. 592,445. (No model.)

To all whom it may concern:

Be it known that we, ALLEN D. LINN and ROBERT W. IRWIN, citizens of the United States, residing at Grand Rapids, in the county of Kent and State of Michigan, have invented certain new and useful Improvements in Back-Lock Fastenings for Chairs, &c., of which the following is a specification, reference being had therein to the accompanying drawings.

Our invention is an improved locking device designed to fasten together the backs of chairs, such as are now used in opera-houses, churches, and like places; and the object of the invention is to provide a simple construction between adjacent chairs by means of which the two chairs are simply and securely locked together and to the standard and after being secured to the floor the entire series are firm and rigid.

In the accompanying drawings we have shown in Figure 1 a side elevation of a part of a standard which is located at the junction of two chair-brackets, the locking means being shown in section. Fig. 2 is a rear view of Fig. l, with the standard in section. Fig. 3 is a horizontal section on line a b of Fig. 1.

In the drawings the rear standard between the seat-backs is shown at g and is made of I-iron, one flange of the I passing to the front of thebacks, as shown in Fig. 3, the adjacent edges of the backs being snugly fitted in the angles formed by the front flange and the rearwardly-extending part of the standard. We aim to lock the seat-backs securely to the standards in the simplest manner possible, and to do this we first form an elongated slot in the standard, as shown at 2', Fig. 1, and secured by a bolt and nut to each adjacent end of the seat-back on the rear face in line with each other are lugs h. These lugs overhang the edges of the seat-backs, as shown in Fig. 3, and their ends are provided with lips,

forming slight hooks, as at h, these lips being adapted to engage the standard about the edges of the elongated slot.

In positioning the parts we first take one back and insert the lug 72. into the slot '5 in its proper position, and it will be seen that the lip engages the rear edge of the slot 2', while the end of the seat-back finds a firm bearing against the web of the standard. The space between the lug of the first seat-back inserted and the front wall of the slot is just sufficient to receive the end of the lug secured to the other seat-back, butby reason of its hooked formation it cannot be inserted directly; but as the slot 1' is in extent a little more than double the height of the lugs it is only neces sary to raise the seat-back to which the second lug is secured, insert the lug into the upper part of the slot 4., bring the end of the lug in line with the space between the first lug and the first wall of the slot, and then slide it down into its proper position, as shown in Fig. 1, in which position its hooked end fits over the edge of the inner wall of the slot, the end of the seat-back enters the angle formed by the front flange and web of the standard, and the contact of the lugs with each other holds the parts snugly in position.

IVhat we claim is In combination, a standard having a front flange and an extending web, seat-backs fitted to the angle formed at the juncture of said flange and web and locking-lugs engaging a slot in the standard and overlapping each other, substantially as described.

In testimony whereof we affix our signatures in presence of two witnesses.

ALLEN D. LINN. ROBERT W. IRWIN. \Vitnesses:

L. T. GIBSON, J. II. MEeREw. 

